Insensitive pressable explosive

ABSTRACT

An insensitive pressable explosive with a high level of energy comprises octogen grains or hexogen which are coated with a polysiloxane solution.

[0001] The invention relates to an insensitive, pressable and castable explosive and a process for the production of said explosive, as set forth in the classifying portion of claim 1.

[0002] The invention is based on a phlegmatised explosive, corresponding to EP 0 509 200 B1 and DE 40 06 961. This involves explosive mixtures in which the particulate explosive is coated with a phlegmatising inert binder. Improved insensitivity is achieved with those binders. In the meantime the demands in respect of insensitivity have been set at a markedly higher level. Those demands are not attained by the known binders.

[0003] The object of the invention is to propose a high-energy, insensitive pressable explosive.

[0004] The invention attains that object in accordance with the characterising features of claim 1 and in accordance with the process claim respectively.

[0005] The invention advantageously provides that an at least monomolecular layer is applied to the crystals of the explosive and fills surface flaws. That eliminates very fine pores which otherwise act as so-called hot spots, with the effect that the explosive reacts in an unwanted fashion when subjected to a relatively low level of loading. The complete wetting effect provides that a high-energy explosive already achieves virtually a 100% theoretical density with just a low inert proportion. As a result, because of the virtually zero porosity of the explosive charge, this affords a further enhanced level of insensitivity with an increased degree of efficiency. This explosive is suitable for shaped charges and fragmentation charges.

[0006] An explosive having the following composition: octogen (HMX) 96% 70% Class 3, grain size <500 μm 30% Class 2 DOA  3% Hy Temp  1% xpolysiloxane, rain′x ® 1°/00

[0007] DOA is the abbreviation for dioctyl adipate and serves as a plasticiser.

[0008] Hy Temp is a trade mark of ZEON Chemicals L.P., 4111 Bells Lane, Louisville, Ky. 40211, and belongs to the chemical family of polyacrylic polymers.

[0009] rain'x® is a mark of Unelko Corporation in the USA.

[0010] There are three suitable alkyl polysiloxanes, namely

[0011] dimethyl polysiloxanes

[0012] methyl hydrogen polysiloxanes, and

[0013] methylphenyl polysiloxanes.

[0014] 1. The production process comprises the following steps:

[0015] Octogen in an amount of 70 parts of coarse grain is mixed with 30 parts of fine grain in a container.

[0016] 2. A polyalkylsiloxane solution is diluted with isopropanol in a ratio by volume of 1:6, added to the explosive mixture and stirred until complete wetting has taken place.

[0017] 3. The mixture is dried.

[0018] 4. In a suction filtration apparatus the slurry is washed 3 to 4 times with distilled water and sucked away as far as possible.

[0019] 5. The mixture is dried.

[0020] 6. In parallel therewith a solution is made up from 1 part of Hy Temp and 3 parts of DOA in 25 parts of solvent mixture comprising 60% ethanol, 20% acetic acid ethyl ester and 20% acetone.

[0021] 7. The dried, pretreated explosive mixture is added to the prepared binder solution in a Drais mixer and mixed at 40° C. for about 1-2 hours with same at a medium agitation speed (rotary speed 60/min).

[0022] 8. The solvent is completely removed with continuing agitation under a pump vacuum, duration about 2 to 3 hours, wherein finally a dry pressable granular material with an approximately 1 to 2 mm particle diameter is produced.

[0023] The production process is to be carried out in an equivalent fashion, on the basis of hexogen. 

1. An insensitive pressable explosive, characterised in that the explosive comprises: octogen or hexogen 92-97% by weight DOA 1-6% by weight Hy Temp 0.5-2% by weight and polysiloxanes 1-5o/oo.
 2. An explosive according to claim 1 characterised in that the octogen or hexogen comprises 70% by weight of coarse grain and 30% by weight of fine grain.
 3. An explosive according to claim 2 characterised in that the grains of the octogen or hexogen are wetted with polysiloxane.
 4. An explosive according to claim 1 characterised in that the binder proportion is 2-8% by weight.
 5. An explosive according to claim 4 characterised in that the binder comprises 1 part of Hy Temp 3 parts of DOA in 25 parts of solvent mixture comprising 60% of ethanol, 20% of acetic acid ethyl ester and 20% of acetone.
 6. A process for the production of the explosive according to claim 1 characterised in that
 1. the coarse grain and the fine grain are mixed,
 2. a solution of polysiloxane solution and isopropanol is added with agitation to the mixture,
 3. the mixture is dried and washed, and
 4. a binder solution comprising 1 part of Hy Temp and 3 parts of DOA in 25 parts of solvent mixture is meteredly added to the mixture and mixed therewith, wherein the binder solution is removed under vacuum with continuous agitation. 